Plano



Dec. 27, 1932. F J, wl wElsER 1,892,296

` PIANO Filed March 31, 1932 n J\ gdr 16 f 'witness'.fg Ef. 9%3 nity.

A, Patented Dec. 277, `1932 UNITED STATES;

FRANK J'. W. WEISER, 0F ELMHURST, ILLINOIS PIANO Application med March a1, 193e. serial No. 602,208. I

My invention provides means to hold the sounding-board of aV piano in its original arched position and thereby keep its crown, and consists in the matters hereinafter described and pointed out in the appended claims.

'After pianos have been used thereA isa tendency for the surface of the. soundingboard to curve or pull away kfrom the strings,

so that the original arching or crown of the board is not maintained, with the result that the pressure of the strings on the bridge is lessened and the tone is rnot so strong. Also,

at times dampness causes the'sounding-board to buckle or become distorted which destroys its original arching of the board and impairs thertone.

The object of my invention is to obviate these objections, and to' provide simple and"k 0 eihcient means whereby the crown or arch ol the sounding-board isretained in its original position and the pressure of the strings on the bridge at the time the instrument was made is maintained. Also, by my invention the string-bridge and ribs are kept from loosening romthe sounding-board, and the board is rendered more rigid without impairing its requisite vibration. My invention gives the piano a more liquid and singing tone.

In the accompanying drawing, which illustrates an embodiment of my invention-Figure 1 is a front view of a piano sounding- 3V board and bridge on which the strings are view of the same sounding-board showing the application of my duplex bridge to the ribs of the board, and Figure 3 is a detail sectional View on the line 3-3 in Figures .10 1 and 2.

In the drawing the reference numeral 10 represents a conventional crowned soundingboard secured to the usual back-frame (not shown) and having on its front the usual treble bridge 11 and bass bridge 12 over which the piano strings indicated generally at 13y are stretched yin the customary manner. The

yboard is provided on its back with the usual ribs 14 andthe acoustic rim or lining 15 along its edges.

. strung in the usual manner; Figure 2 is rear In carrying' out my invention I apply to f the back of the sounding-board a duplex tone-bridge of the same contour or configuration as the string-bridge on its front. The duplex tone-bridge consists of a treble mem- '55 ber A16 corresponding in length and contour with the treble bridge 11, and a bass member 17 corresponding in length and contour withk the bass bridge 12.` rIhese tone-bridge members are wooden strips and are attached rmly tothe back-ribs 14. In assembling the parts the string-bridges 11 and 12 are secured to the front of the sounding-board in the usual way, generally by gluing them in place, and the tone-bridge members 16 and 17 arey 65 secured to the back ribs 111 of the soundingboard in alinement or registry with the front bridges 11 and 12 respectively by gluing them to the ribs at their intersections therewith, and also preferably by screws 18 passing 70 through the tone-bridge members, the underlyingribs and the sounding-board, and

yinto the associated string-bridge members.

This method of assembly is shown in Figure 3, where the screws 18pass through the tone- 75 bridge member 16, two of the ribs 14; and the sounding-board 10, and seat in the treble string-bridge member 11. v

By this organization the duplex tonebridge holds the sounding-board in its original position and so lpreserves vthe crown of the board, and it also keeps the string-bridge members and the ribs from working loose from the sounding-board. The original pressure of the strings on the string-bridge is maintained, the board 'is made more rigid to resist distortion without impairing its vibration, and the piano has a more liquid tone.

In practice I may use only the treble member 16 of the tone-bridge in small pianos, as in this type of pianos the crown of the board is preserved and the ribs spanned by the bass member 12 of the string-bridge are suiiciently braced by the treble member 16 to 95 secure the above advantages.

I claim: f

1. A crowned sounding-board having treble and bass .string-bridge members on its kfront and ribs on its back, and ya duplex 109 bridge consisting of separate members having respectively substantially the same configuration as said string-bridge members and secured upon the ribs in substantial registry with their corresponding string-bridge members, all of said bridge members being independent of the string-plate.

2. A crowned sounding-board having treble and bass string-bridge members on its front and ribs on its back, a supplemental bridge member having substantially the same contour as said treble bridge member and mounted on the ribs in registry with said treble bridge member, all of said bridge members being independent of the string-plate.

3. A crowned sounding board having treble and bass string-bridge members on its front and ribs on its back, a duplex bridge consisting of independent members respectively corresponding in contour with said string-bridge members and each crossing a plurality of said ribs, and screws passing through said duplex bridge members and their underlying ribs and said board and seating in said string-bridge members, all of said bridge members being independent of the string-plate. Y

In testimony whereof I aiix my signature.

FRANK J. YV` VVEISER. 

